PostFader V12 — FL Studio MCP Server

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channel_get_steps

Read-onlyIdempotent

Read a channel's step-sequencer grid in the current pattern, returning each step's on/off state and a digest to guard later edits against stale data.

Instructions

Read one channel's step-sequencer grid in the current pattern.

Read-only. Returns each step's on/off state and a digest of the grid. Pass
that digest as channel_set_steps' expected_digest so the edit refuses if
the grid changed in between. The pattern must be the current one; select
it first with pattern_set(select=true).

Input Schema

TableJSON Schema

Name	Required	Description	Default
`channel_index`	Yes	Global Channel Rack index from channel_list.
`pattern_number`	Yes	Pattern to read; it must be FL's current pattern (see pattern_list).

Output Schema

TableJSON Schema

Name	Required	Default
`cells`	Yes
`digest`	Yes
`warnings`	No
`step_count`	Yes
`index_scope`	No	global
`observed_at`	Yes
`channel_index`	Yes
`pattern_number`	Yes
`schema_version`	No	1.0
`grid_resolution`	No	sixteenth_note
`digest_algorithm`	No	sha256-canonical-json-v1
`observation_atomic`	No
`project_dirty_flag`	No
`current_pattern_number`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Addedv11.0.2Oct 5, 2026

TDQS

A4.5/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint/idempotentHint/destructiveHint, so the 'Read-only' line is partly redundant. However, the description adds real behavioral context the annotations cannot: the returned digest, its role as an optimistic-concurrency token that makes edits refuse on change, and the current-pattern constraint.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with purpose, then return/behavior, then the prerequisite. Every sentence earns its place with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Even though an output schema exists, the description usefully explains the digest's downstream purpose, and it covers the prerequisite and read-only nature. Nothing an agent needs to call this correctly or chain it with channel_set_steps is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so both parameters are already documented (channel_index from channel_list, pattern_number must be FL's current pattern). The description reinforces the 'current pattern' constraint but adds no syntax or format detail beyond the schema; baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Read one channel's step-sequencer grid') and scope ('in the current pattern'). Clearly distinguishable from channel_set_steps and pattern_list without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly ties usage to a companion workflow: it tells the agent to pass the returned digest as channel_set_steps' expected_digest. It also states the prerequisite that the pattern must be the current one and names pattern_set(select=true) to satisfy it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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